There is considerable gap in time between submitting applications for academic positions and the time the postitions start. I'm wondering about the status of the problems listed in the research proposal during this gap. Are they off-limits and should be avoided, or is it OK to work on/think about them in the meantime? Suppose that I show up at the new institution already with a preprint on arXiv solving one of the problems from my research proposal - would it be considered inappropriate?
[My field is pure mathematics, meaning that the research tends to be relatively unpredictable and does not require external resuorces.]